[SPOILERS] BioShock Infinite Story Explained?

Alright, I can't wait any longer, and I've seen at least a few people finished the game, so I'd like to discuss the ending and the whole story of BioShock Infinite, or actually, just the world of BioShock.

1. If Booker is Comstock, how did they both meet each other?
2. If Booker is Comstock, and created Columbia, then how come he "forgot" that its him?
3. If Booker is Comstock, how come they look like two different people?

4. The Luteces tried multiple times already to send Booker to Columbia to free Elizabeth from "himself", but it has always ended in him being killed by the Songbird (that's why they know which number (77) he's going to pick at the raffle, etc.), but I don't understand what changed THIS TIME? What has gone differently for him to go beyond that point where he [Booker] would normally fail and die?

I see that that has something to do with different realities, but I still can't manage to put the pieces together.

I suspect that 2nd question is just Booker living in another dimension/universe/reality/world, where he didn't became rich and didn't create Columbia, but I need that confirmed.

I'm very curious if someone has a grip on all of these. I might have just missed some important detail or something during the dialog in the game.

the thing is you have to remember we have multiple timelines going on, the game explores the idea of a parallel universe. Cornstock is born if Booker accepts baptism. Assuming you watched all the way through the end, you will remember then that near the ending booker and elizabeth go to different tears and the baptism place (in the small prarie). If booker accepts baptism he becomes reborn and changes his name to zachery cornstock. If he refuses baptism, then he is still booker and continues on his gambling ways.
just read these

1. The Luteces brought Booker (one one you play as) into the parallel universe where Columbia exists (the tear they brought you through was the door that Booker kept walking through).

2. Booker didn't know he was Comstock at all because in Booker's universe, he never went through with the baptism, and thus, never became Comstock.

3. Comstock was with the Luteces as they did experiments with the tears, which, according to a voxophone, aged Comstock quicker than normal.

4. In other universes, Booker kept fighting Songbird to free Elizabeth and kept getting killed. For this Booker, another Elizabeth (the one who destroyed New York) gave him a card telling him how to prevent Booker from fighting with Songbird. The card gave Elizabeth the notes needed to call Songbird and get his help instead of ending up in battle with him.

That wasn't actually used in the final game; that was from an earlier build. They may not have had the entire story planned out at that point or maybe they used it as a placeholder for the early trailers, since they may not have had a final design for Comstock at the time.

I love this story it was so damn good, I like how they had the "AD" carved right into booker's hand but you never really questioned it, until the end when you find out she is your daughter and what her name really is

Just finished the game: jeez what a ride! Good story, lots to discus and debate about.

I'm left with a feeling though, and after scouring the forums and message boards trying to have that feeling validated, I'm sad to say no-one seems to make a mentioning of the following:

Booker's debt, and especially who he owes it to, is only ever hinted at. Snippets like "he owed money to the wrong people" and "he took up gambling" is all the game offers us. But after finishing the game, I interpret the debt as follows:

Booker does something horrible at wounded knee, feels horrible about it, takes up drinking and gambling, gets into trouble, sells anna after comstock (himself in a different dimension) reaches out to him through robert lutece and his/her technology. booker hands over the baby (we know exactly how that went because we get to play that scene) to robert who says "Comstock absolves you of your sins"

What? wait! hold the plucking phone! "Absolution?" That is not the same as paying a debt. No money is exchanged, no mentioning of debts being paid to another party except for "COMSTOCK (yes, booker HIMSELF in an alternate reality) absolves BOOKER of his sins. You absolve yourself of your sins, across time and space.

I think Booker's debt had nothing to do with money or gambling (which is an interesting concept, btw, if you place it amidst a story line that is about infinite options and outcomes... Whether you place your next bet on black or red, whether you go all in or go home, some part of you, somewhere in time and space, wins big, looses, and never goes to the cassino in the first place) but simply with guilt. There are no "wrong people" but himself: booker. He says (I can't remember when) that the world needs protection "from men like him", meaning both booker and comstock.

So: booker does something horrible at wounded knee, has anna and gives her to his alternate self (the one that found absolution through babtism) because that is the only way HE CAN FORGIVE HIMSELF for what has happened. He then realises that absolution is bull (several other's have pointed out that booker's an atheist, so absolution is hardly impressive to him).